View
0
Download
0
Category
Preview:
Citation preview
ダークマターとCTA
Physics Department, Tohoku University Physics Department, Tohoku University
(郡 和範)Kazunori KohriKazunori Kohri
http://map.gsfc.nasa.gov/media/060916
Dark Matter?
2CDM 0.1Ω ∼h
0
ii
c
ρρ
Ω ≡
What is Dark Matter?• It is massive (ρ∝a-3)
• It is stable (τ>> 10 18 sec)
• It does not scatter off photons so much( Is it a bound-state?)
• It is neutral (from experiments of sea water m<106 GeV)
• The velocity dispersion is small [cold dark matter (CDM)]
Candidate of particle (cold) dark matter• Stable or long-lived new particle
• Oscillating scalar field
• Neutralino• Gravitino• Right-handed sneutrino• Axino• …
• Axion• Moduli• …
Another candidates
• Primordial black hole• Brown dwarf• WIMPZILLA• Integral constant in Horava-Lifshitz gravity• Quark nugget (strange-quark matter)• Solutions in (relativistic-) Modified
Newtonian Dynamics (MOND)• …
Rotation curve
二間瀬敏史著 「なっとくする宇宙論」
( )M r r∝ Begeman, Broils,Sandars etal (91)
Dark Halo
gas
Stars (visible component)
Gravitational lens in colliding cluster of galaxies
• Red: Baryon observed by X-ray produced by bremsof thermal electron
• Blue: DM observed by gravitational lens
(2007)
Time-evolution of fluctuation III
Ma and Bertschinger (95)
See also 松原隆彦 「シリーズ 現代の天文学3 宇宙論 II 宇宙の進化」
-6 -5 -4 -3 -2 -1
Log a
(II) Horizon reentry before matter-radiation equality epoch
∝a
∝a2
aEQ
Cluster baryon fraction
• Cluster can have a representative distribution in the Universe of both baryon and DM
• Ωbh2 is independently known, fgas was observed by X-ray from Oxygen
Ωm~ 0.2
Combined Figure
Riess et al (98), Lahav-Liddle PDG (09)
Fermion Boson
Introduction toIntroduction to SUSYSUSYSupersymmetry (SUSY)
Solving “Hierarchy Problem”
Realizing “Coupling constant unification in GUT”
quark squark
lepton slepton
gravitino graviton
photino photonneutralino
Depending on SUGRA models
12-13 orders of magnitude !!!
Hierarchy ProblemsHierarchy Problems
≈ 14 1510 - 10 GeVXM
≈ 2 310 -10 GeVWM
GUT-scale
Weak-scale
Higgs mass 22 20 2
2 ( )Wd Vm O Md
ϕϕ υλ
ϕ= ≈ ≈
( )ϕ λ ϕ ϕ υ= −2† 2 /2V
where Higgs’s potential
ϕ
Vϕ
~υc.f) Masses of fermions and vector bosons
ψ ψ ϕ ϕ~ , ~Zm h m g
Radiative correction to Higgs mass Radiative correction to Higgs mass in Quantum Field Theoryin Quantum Field Theory
ϕδ λΛ + Λ2 2 2 2~m gλϕ ϕ
ϕ
ϕ ϕg g
W
Λ 15Cut off scale ~ ~ 10 GeVXM
+
( )ϕδ22 15~ 10 GeV ?m
Quadratic divergence
How can we resolve the problem?How can we resolve the problem?Weak scale in the tree level, ( )
( )21
220
2 5
2~ 10 GeV
~ 10 GeV
m
mϕ
ϕ
δ
( )ϕϕ ϕ δ+
222 2 15 0 ~~ 10 GeV ?m mm
To retain the hierarchy, we require an accidental cancellation,
( )ϕ ϕ ϕ ϕδ δ δ+ + + +22 2 2 2 2
0 1 2 3 ... ~ 10 GeV ?m m m m
⎡ ⎤⎣ ⎦215(10 GeV)O
Fine tuning!Fine tuning!
In total,
$ 10,110,087,734,958.95-) $ 10,110,087,734,957.70
$ 1.25
GDP in USA (2002)?
Solution in SUSYSolution in SUSYIn exact SUSY, the quadratic divergence is canceled by both boson and fermion loops.
2thϕ ϕ
t
+ 0=ϕ ϕ
tth th
Exact SUSY2 2
2
1(4 ) thπ
Λ2 22
1 (4 ) thπ
− Λ
Even if SUSY,
ϕδπ
⎛ ⎞Λ⎜ ⎟⎜ ⎟⎝ ⎠
∼ 2
2
22 2
2
1ln
(4 )t
t
th m
mm
We don’t need a fine tuning when
∼ ∼ ∼2 2 2... ( )t Wb
mm OM
SUSY GUTSUSY GUT
The coupling constants are unified at
≈ 1610 GeVXM
A lot of new particles ,which do not obey the asymptotic free, appear at
μ ≥ 210 GeVMartin, ”A Supersymmetry Primer”
Lightest SUSY particle (LSP)• R-parity conservation
i)Decay
ii) Pair annihilation/production
τ χ τ→ +
χ χ+ ↔ +f f
(-1) (-1)×
(-1)× (-1)
(+1)
(+1) ×(+1)
Thermal freezeoutBoltzmann equation
frezeout
3χ σ∼ Hn
v
( )2
20.10.1
TeVχ
σ⎛ ⎞⎜ ⎟Ω ⎜ ⎟⎜ ⎟⎝ ⎠
∼v
h
Freezeout / 30χ∼T m
Ωχ does not depend on mχ
Kolb & Turner
Predicting TeV Physics!!! 26 33 10 /v cm sσ −= ×
Positron Excess (PAMELA satellite reported)
Adriani et al, arXiv:0810.4995v1 [astro-ph]
/ ( ~0.6 proton diffusion)e e E δ δ+ − −∝
Electron and positron flux by ATIC2
Chang et al (08)
Electron and positron flux by Fermi
Abdo et al, Fermi LAT Collaboration, arXiv:0905.0025, PRL102 (09) 181101
Hisano, Kawasaki,
Kohri, Moroi, Nakayama (09)
Positron excess
in DM annihilation
Diffusion model
Fitted to B/C ratio
24 23 310 10 /v cm sσ − −−∼
Hisano, Kawasaki,
Kohri, Moroi, Nakayama (09)
Electron/positron cutoff
in DM annihilation
23 310 /v cm sσ −∼
Kawasaki, Kohri, Nakayama (09)Gamma-ray signal from GC by DM annihilation
Kawasaki, Kohri, Nakayama (09)
Extragalactic diffuse Gamma-ray by DM annihilation
Fitting by Papucci and StrumiaPapucci, Strumia, arXiv:0912.0742 [hep-ph]
See also Chen, Mandal and F. Takahashi, arXiv:0910.2639 [hep-ph]
CTA?
Courtesy of Kazunori Nakayama
Result of Papucci and StrumiaPapucci, Strumia, arXiv:0912.0742v1 [hep-ph]
Extragalactic diffuse-gamma
CTA?
Direct detection by CDMSII
2recoil
1~ ~ (10)keV2μE v O
-3~ 220km/s (v/c~10 )v
Ge DM
Ge DM
~ m mm m
μ+
Ge 72.6 um =
Ge DMm m
arXiv:0912.3592v1 [astro-ph.CO]
M < O(100) GeV? (Farina et al)
Background
0.8 ±0.1(stat) ±0.2(syst)
arXiv:0912.5038v1 [hep-ph]Marco Farina, Duccio Pappadopulo, Alessandro Strumia
ConclusionConclusion• Fermi may not exclude the possible scenarios
for the positron/electron excess by the DM annihilation/decay because of the upper limit on the sensitivity (<300 GeV)
• CTA will be able to verify those scenarios
• CTA may have a sufficient sensitivity to detect gamma-rays associated with DM annihilation even with its canonical annihilation cross section (~3×10-26 cm3/s)
Recommended